The present invention relates to an automatic transmission control device and, particularly, to such a device which is capable of temporarily reserving or delaying the automatic switching of a gear change mechanism of the automatic transmission to either one of two shift patterns when the device decides the switching is not intended by an operator.
In a conventional electronically controlled automatic transmission, it is usual that the shift pattern which establishes the timing of gear shifts can be changed automatically or intentionally in order to match the shift pattern with a running mode desired by an operator or a change in the output characteristics of the engine. An example of such transmission is shown in Japanese Patent Publication No. 3981/1986.
In such an automatic transmission, there may be a gear change caused by the gear change mechanism thereof immediately after the shift pattern is switched from one to the other, while the accelerator pedal is not operated by an operator so that the vehicle speed is unchanged. That is, when the gear change mechanism of the automatic transmission is switched from a shift pattern covering a high speed range to a shift pattern covering a low speed range, a down-shift occurs, resulting in an undesired deceleration. This is particularily true when the switching between the shift patterns is performed automatically.
Since, in order to solve this problem, it is necessary to make respective shift patterns much closer to each other, it is very difficult to provide shift patterns having considerable mutual differences.